1. Field of the Invention
The present invention relates to a frame deformation control apparatus. More specifically, the present invention relates to an apparatus which can surely cause an axial deformation on a frame by controlling an active deformation of the frame.
2. Description of Relevant Art
Conventionally, to deform a frame of vehicle (vehicle frame) in a longitudinal direction thereof while restricting a bending deformation on middle of the frame has been required, in order to absorb a collision energy caused by a collision. Here, a longitudinal direction's deformation without bending deformation of the frame is called as “axial deformation”.
As an example of these kinds of technique, the technique disclosed in Japanese unexamined patent publication No. 2000-168624 has been discovered. In this patent publication, a special bracket, which connects a power unit, such as a transfer or an engine disposed in the middle of a vehicle body, with side-frames, which hold the power unit from both sides thereof, is disclosed. By using this special bracket, a bending moment to be added to the side-frame can be cancelled.
As the other example, the technique disclosed in Japanese unexamined patent publication No. H10-129521 has been discovered. In this patent publication, a side-frame, onto which a pair of non-parallel slots is formed, is disclosed. In this side frame, if a collision had occurred, since a bending moment is intentionally induced at the region in the vicinity of the non-parallel slots, the bending moment caused by the collision is cancelled by the bending moment to be caused by slots.
In these conventional techniques, however, the bending moment to be caused on the region near the bracket or slots is cancelled with a reverse moment, which acts in a reverse direction with respect to the direction of the bending moment and which is caused as a result of the occurrence of the bending moment caused by the collision.
That is, in these conventional techniques, since the bending moment due to the collision is cancelled with the passively-caused reverse moment, the reverse moment does not necessarily correspond to the bending moment.
In case of the frame adopting a conventional technique, therefore, it is difficult to cause an axial deformation (crush) prior to the bending deformation of the frame, and thus the bending deformation of the frame may be caused prior to the axial deformation.
In case of the frame adopting a conventional technique, in which the bending moment is cancelled with the passively-caused reverse moment, the stiffness of the frame can not be changed in compliance with parameters, such as a collision rate and the position of an occupant.
In case of the frame adopting a conventional technique, furthermore, as the length of the frame becomes longer, it is difficult to cause only the axial deformation (crush) of the frame without causing the bending deformation.
This is because of the following reason. In case of the conventional technique, the position where the bracket or the slot is provided is determined in anticipation of the region where the bending moment to be caused by a collision is concentrated. Thus, as the frame becomes long, since the bending moment tends to be applied locally to another region where the bracket or the slot is not provided, the frame may cause the bending deformation on this region.
If the bending deformation arises on the frame, the efficiency of energy absorption of the collision energy as a whole becomes worse.
Therefore, a frame deformation control apparatus, which can surely cause an axial deformation on the frame prior to the bending deformation even if the length of the frame becomes longer, and can control the stiffness of the frame in compliance with parameters, such as a collision speed (rate) and the position of an occupant, has been required.